package com.codemes.happylist.lucene;

/**
 * @author <a href="mail:fulei@fehorizon.com">fulei</a>
 * @date 2022/8/22 16:34
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.annotation.Retention;
import java.nio.charset.StandardCharsets;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.*;

import cn.hutool.core.io.FileTypeUtil;
import cn.hutool.core.io.FileUtil;
import cn.hutool.json.JSONUtil;
import com.codemes.happylist.lucene.analyzer.IKAnalyzer;
import com.codemes.happylist.lucene.knn.DemoEmbeddings;
import com.codemes.happylist.lucene.knn.KnnVectorDict;
import com.codemes.happylist.lucene.reader.FileTextReader;
import com.codemes.happylist.lucene.reader.FileTypeEnum;
import com.codemes.happylist.lucene.reader.office.ExcelFileTextReader;
import com.codemes.happylist.lucene.reader.office.PptFileTextReader;
import com.codemes.happylist.lucene.reader.office.WordFileTextReader;
import com.codemes.happylist.lucene.reader.pdf.PdfFileTextReader;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.KnnVectorField;
import org.apache.lucene.document.LongPoint;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.VectorSimilarityFunction;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.IOUtils;
import org.springframework.util.MimeTypeUtils;

/**
 * Index all text files under a directory.
 *
 * <p>This is a command-line application demonstrating simple Lucene indexing. Run it with no
 * command-line arguments for usage information.
 */
public class IndexFiles implements AutoCloseable {
    static final String KNN_DICT = "knn-dict";

    // Calculates embedding vectors for KnnVector search
    private final DemoEmbeddings demoEmbeddings;
    private final KnnVectorDict vectorDict;

    static Set<String> fileTypeList = new HashSet<>();

    private IndexFiles(KnnVectorDict vectorDict) throws IOException {
        if (vectorDict != null) {
            this.vectorDict = vectorDict;
            demoEmbeddings = new DemoEmbeddings(vectorDict);
        } else {
            this.vectorDict = null;
            demoEmbeddings = null;
        }
    }

    /** Index all text files under a directory. */
    public static void main(String[] args) throws Exception {
        String usage =
            "java org.apache.lucene.demo.IndexFiles"
                + " [-index INDEX_PATH] [-docs DOCS_PATH] [-update] [-knn_dict DICT_PATH]\n\n"
                + "This indexes the documents in DOCS_PATH, creating a Lucene index"
                + "in INDEX_PATH that can be searched with SearchFiles\n"
                + "IF DICT_PATH contains a KnnVector dictionary, the index will also support KnnVector search";
        String indexPath = "D:\\data\\lucene\\demo";
//        String indexPath = "index";
        String docsPath = "D:\\天翼云盘同步盘\\18914966247\\宏信\\面试简历";
//        String docsPath = null;
        String vectorDictSource = null;
        boolean create = true;
        for (int i = 0; i < args.length; i++) {
            switch (args[i]) {
                case "-index":
                    indexPath = args[++i];
                    break;
                case "-docs":
                    docsPath = args[++i];
                    break;
                case "-knn_dict":
                    vectorDictSource = args[++i];
                    break;
                case "-update":
                    create = false;
                    break;
                case "-create":
                    create = true;
                    break;
                default:
                    throw new IllegalArgumentException("unknown parameter " + args[i]);
            }
        }

        if (docsPath == null) {
            System.err.println("Usage: " + usage);
            System.exit(1);
        }

        final Path docDir = Paths.get(docsPath);
        if (!Files.isReadable(docDir)) {
            System.out.println(
                "Document directory '"
                    + docDir.toAbsolutePath()
                    + "' does not exist or is not readable, please check the path");
            System.exit(1);
        }

        Date start = new Date();
        try {
            System.out.println("Indexing to directory '" + indexPath + "'...");

            Directory dir = FSDirectory.open(Paths.get(indexPath));
//            Analyzer analyzer = new StandardAnalyzer();
            Analyzer analyzer = new IKAnalyzer();
            IndexWriterConfig iwc = new IndexWriterConfig(analyzer);

            if (create) {
                // Create a new index in the directory, removing any
                // previously indexed documents:
                iwc.setOpenMode(OpenMode.CREATE);
            } else {
                // Add new documents to an existing index:
                iwc.setOpenMode(OpenMode.CREATE_OR_APPEND);
            }

            // Optional: for better indexing performance, if you
            // are indexing many documents, increase the RAM
            // buffer.  But if you do this, increase the max heap
            // size to the JVM (eg add -Xmx512m or -Xmx1g):
            //
            // iwc.setRAMBufferSizeMB(256.0);

            KnnVectorDict vectorDictInstance = null;
            long vectorDictSize = 0;
            if (vectorDictSource != null) {
                KnnVectorDict.build(Paths.get(vectorDictSource), dir, KNN_DICT);
                vectorDictInstance = new KnnVectorDict(dir, KNN_DICT);
                vectorDictSize = vectorDictInstance.ramBytesUsed();
            }

            try (IndexWriter writer = new IndexWriter(dir, iwc);
                IndexFiles indexFiles = new IndexFiles(vectorDictInstance)) {
                indexFiles.indexDocs(writer, docDir);

                // NOTE: if you want to maximize search performance,
                // you can optionally call forceMerge here.  This can be
                // a terribly costly operation, so generally it's only
                // worth it when your index is relatively static (ie
                // you're done adding documents to it):
                //
                // writer.forceMerge(1);
            } finally {
                IOUtils.close(vectorDictInstance);
            }
            System.out.println(JSONUtil.toJsonStr(fileTypeList));
            Date end = new Date();
            try (IndexReader reader = DirectoryReader.open(dir)) {
                System.out.println(
                    "Indexed "
                        + reader.numDocs()
                        + " documents in "
                        + (end.getTime() - start.getTime())
                        + " milliseconds");
                if (reader.numDocs() > 100
                    && vectorDictSize < 1_000_000
                    && System.getProperty("smoketester") == null) {
                    throw new RuntimeException(
                        "Are you (ab)using the toy vector dictionary? See the package javadocs to understand why you got this exception.");
                }
            }
        } catch (IOException e) {
            System.out.println(" caught a " + e.getClass() + "\n with message: " + e.getMessage());
        }
    }

    /**
     * Indexes the given file using the given writer, or if a directory is given, recurses over files
     * and directories found under the given directory.
     *
     * <p>NOTE: This method indexes one document per input file. This is slow. For good throughput,
     * put multiple documents into your input file(s). An example of this is in the benchmark module,
     * which can create "line doc" files, one document per line, using the <a
     * href="../../../../../contrib-benchmark/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.html"
     * >WriteLineDocTask</a>.
     *
     * @param writer Writer to the index where the given file/dir info will be stored
     * @param path The file to index, or the directory to recurse into to find files to index
     * @throws IOException If there is a low-level I/O error
     */
    void indexDocs(final IndexWriter writer, Path path) throws IOException {
        if (Files.isDirectory(path)) {
            Files.walkFileTree(
                path,
                new SimpleFileVisitor<>() {
                    @Override
                    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
                        try {
                            indexDoc(writer, file, attrs.lastModifiedTime().toMillis());
                        } catch (
                            @SuppressWarnings("unused")
                            IOException ignore) {
                            ignore.printStackTrace(System.err);
                            // don't index files that can't be read.
                        }
                        return FileVisitResult.CONTINUE;
                    }
                });
        } else {
            indexDoc(writer, path, Files.getLastModifiedTime(path).toMillis());
        }
    }

    /** Indexes a single document */
    void indexDoc(IndexWriter writer, Path file, long lastModified) throws IOException {
        try (InputStream stream = Files.newInputStream(file)) {
            // make a new, empty document
            Document doc = new Document();

            // Add the path of the file as a field named "path".  Use a
            // field that is indexed (i.e. searchable), but don't tokenize
            // the field into separate words and don't index term frequency
            // or positional information:
            Field pathField = new TextField("path", file.toString(), Field.Store.YES);
            doc.add(pathField);

            // Add the last modified date of the file a field named "modified".
            // Use a LongPoint that is indexed (i.e. efficiently filterable with
            // PointRangeQuery).  This indexes to milli-second resolution, which
            // is often too fine.  You could instead create a number based on
            // year/month/day/hour/minutes/seconds, down the resolution you require.
            // For example the long value 2011021714 would mean
            // February 17, 2011, 2-3 PM.
            doc.add(new LongPoint("modified", lastModified));

            // Add the contents of the file to a field named "contents".  Specify a Reader,
            // so that the text of the file is tokenized and indexed, but not stored.
            // Note that FileReader expects the file to be in UTF-8 encoding.
            // If that's not the case searching for special characters will fail.
            String fileType = FileTypeUtil.getType(file.toFile());
            FileTypeEnum typeEnum = FileTypeEnum.getByCode(fileType);
            FileTextReader fileTextReader =  switch (typeEnum){
                case PDF ->  new PdfFileTextReader();
                case DOC, DOCX ->  new WordFileTextReader();
                case PPTX ->  new PptFileTextReader();
                case XLSX ->  new ExcelFileTextReader();
                default -> null;
            };
            if(null!=fileTextReader){
                doc.add(
                    new TextField(
                        "contents",
                        fileTextReader.readText(file.toFile()),
                        Field.Store.YES
                    ));
            }else{
                doc.add(
                    new TextField(
                        "contents",
                        new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8))));
            }

            if (demoEmbeddings != null) {
                try (InputStream in = Files.newInputStream(file)) {
                    float[] vector =
                        demoEmbeddings.computeEmbedding(
                            new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8)));
                    doc.add(
                        new KnnVectorField("contents-vector", vector, VectorSimilarityFunction.DOT_PRODUCT));
                }
            }

            if (writer.getConfig().getOpenMode() == OpenMode.CREATE) {
                // New index, so we just add the document (no old document can be there):
                System.out.println("adding " + file);
                writer.addDocument(doc);
            } else {
                // Existing index (an old copy of this document may have been indexed) so
                // we use updateDocument instead to replace the old one matching the exact
                // path, if present:
                System.out.println("updating " + file);
                writer.updateDocument(new Term("path", file.toString()), doc);
            }
        }
    }

    @Override
    public void close() throws IOException {
        IOUtils.close(vectorDict);
    }
}